Culturing marine invertebrate larvae and other zooplankton is often difficult. In particular, it is difficult to rear large numbers of invertebrate larvae and other zooplankters for gene expression studies, or to establish healthy cultures for exposure to a variety of experimental conditions.
Prior art methods for rearing marine invertebrate larvae include a method for stirring larval cultures within closed containers using paddles, as disclosed in Strathmann R R (1971), “The Feeding Behavior of Planktotrophic Echinoderm Larvae: Mechanisms, Regulation and Rates of Suspension-feeding”, J Exp Mar Biol Ecol 6: 109-160. An alternative method in the art uses water droplets, as disclosed in Hadfield as quoted in Strathmann M F (1987), “Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast: Data and Methods for the Study of Eggs, Embryos, and Larvae”, University of Washington Press, Seattle and London. Such methods maintain a high concentration of algal food sources for the planktotrophic larvae, but they are not self-cleaning, as water is not continuously cleared from the culturing vessel.
There are techniques in the prior art for rearing marine organisms in an open aquarium having constantly running seawater exiting through a mesh-covered opening. These are inconvenient as more fragile organisms tend to get caught on the mesh-covered opening, due to the excessive force of the water flow. Devices that circumvent this problem are designed to generate gentle water flows, as disclosed in Greve W (1968), “The “Planktonkreisel”, a New Device for Culturing Zooplankton”, Mar Biol 1: 201-203; and Ward W W (1974), “Aquarium Systems for the Maintenance of Ctenophores and Jellyfish and for the Hatching and Harvesting of Brine Shrimp (Artemia salina) Larvae”, Chesapeake Sci 15: 116-118, but they are not a good option for culturing more robust lecithotrophic larvae because they provide insufficient agitation to clear out debris and yolk from eggs that fail to develop properly. A system of cages suspended in flowing water, as disclosed in Høeg J T (1984), “A Culture System for Rearing Marine Invertebrate Larvae and its Application to Larvae of Rhizocephalan Barnacles”, J Exp Mar Biol Ecol 84: 167-172, also does not allow for easy manipulation, sampling, stirring, and collection of individuals in culture, nor does it keep some types of buoyant larvae from being forced onto the ceiling of the enclosure.